Practical Guide to Introducing Spring Boot MongoDB Transactions

To use Multi-Document transactions in MongoDB, you must have a Replica Set or Sharded Cluster environment, and the WiredTiger storage engine is required. Standalone environments do not support transactions because they lack replication functionality.

MongoDB transactions default to the Read Committed isolation level, and use Snapshot Isolation to perform operations based on a snapshot of the data at the time the transaction started. During this process, if another transaction modifies the data, a Write Conflict can occur, so handling this is important.

In a Spring Boot environment, you can finely control Write Concern, which determines data durability, and Read Preference, which adjusts read performance and consistency, through MongoClient configuration.

• Write Concern options: ACKNOWLEDGED, MAJORITY, UNACKNOWLEDGED, W1, W2, FSYNCED, JOURNALED
• Read Preference options: PRIMARY, SECONDARY, PRIMARY_PREFERRED, SECONDARY_PREFERRED, NEAREST